Answer:
Model A
Explanation:
Model A represents an atom that is more reactive than the others represented.
Valence electrons actually determine the reactivity of elements. They also determine the properties of elements.
Elements with one valence electron are highly reactive because they need low energy to remove them. They can either gain more electrons to become stable or they share/give out their electrons.
Therefore, Model A is the correct answer because it has one valence electron and its valence electron is farther from the nucleus thereby this makes it more reactive.
Answer:
(Most accurate) pippete>graduated cylinder>beaker>balance (Least accurate)
Explanation:
- <em>Most accurate. A pipette prived the most accurate method for delivering a known volume of solution, for example, a 10mL transfer pipette has an accuracy of ±0.02mL</em>
- A graduated cylinder is specifically used to deliver a known volume, its typical accuracy is ±1%, this means that a 100ml graduated cylinder is accurate to ±1mL.
- A beaker is a multipurpose cylindrical glass mainly used to hold liquids. Even though they are graduated, these marks are an estimation, the beaker's accuracy is around 10%.
- Least accurate. A balance measures an object's mass, even though water's density is close to 1, a balance is not the ideal equipment to measure volume, its capacity usually goes between 100-200grams and can measure mass to the nearest ±0.01mg to ±1mg.
I hope you find this information useful and interesting! Good luck!
Im pretty sure it weight because when we are on different plants with a different amount of gravitational pull our weight changes
hope this helps :)
Answer: 1. C. polar covalent: electrons shared between silicon and sulfur but attracted more to the sulfur
2. B) 
3. B) Fluorine
Explanation:
1. A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.
Electronegativity difference = electronegativity of sulphur- electronegativity of silicon = 2.5 -1.8 = 0.7
Thus as electronegativity difference is less than 1.7 , the cond is polar covalent and as electronegativity of sulphur is more , the electrons will be more towards sulphur.
2. A molecular compound is usually composed of two or more nonmetal elements. Example:
Ionic compound is formed by the transfer of electrons from metals to non metals. Example: 
, 
and 
3. For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here K is having an oxidation state of +1 and as the compound formed is KZ, the oxidation state of non metallic element Z should be -1. Thus the element Z is flourine which exists as diatomic gas 
<span>A. Exact ecological footprints are often difficult to calculate, but estimates can be useful in comparing populations.
</span>Which of the following could be said about ecological footprints? <u /> <u>Exact ecological footprints are often difficult to calculate, but estimates can be useful in comparing populations.</u><u />
NOT:
b. Ecological footprints can't be used to determine carrying capacity.
C. Ecological footprints don't take into account resources needed to absorb and manage wastes.
<span>D. The average ecological footprints for various countries are nearly identical.</span>
